Tau-square guide



Patented lidar. All, 1924.

@NEFF it-@SEM T-SQUARE GUIDE.

Application :filed 'March 26, 1923.

To all whom t may concern.'

Be it known that I, FRANZ KTTEL, a citizen of the Republic ofSwitzerland, and resident of Lucerne, in the Canton of Lucerne,

Switzerland, have invented'certain new and useful Improvements inT-Square Guides, of which the following is a specification.

rEhe manipulation of loose T-squares along the edges of a drawing boardhas ever been felt as an inconvenience by every draughtsman, inasrnushas he is necessarily obliged always to use one hand for thepurposeofpressing the l`square against and cause it to slide along the board inorder to draw horizontal l5 or vertical lines and parallels thereto. It

not rarely happens hereby that owing to carelessness in holding orguiding the T- square a fresh line, instead of being drawn parallel, isdrawn at an angle to the preceding line. More often, however, foreignbodies become attached to the guiding edge of the drawing board, theT-square being made to slide over these bodies and thereby caused tolose its true bearing. Especially when using large drawing boards, caremust be taken that in guiding the drawing pen or pencil along thecorrespondingly long T- square, the latter, as is frequently the casewhen operating at its end, is not forced out of its true horizontalposition relative to the drawing board, a firm pressure of the T-squareagainst the edge of the board being essential in order to maintain suchtrue horizontal position of the fsquare.

It is the object of the present invention to enable the draughtsman notonly to keep the T-square constantly in the required horizontalposition, but also to permit of an easy adjustment and fixing of theT-square at any desired point along the edge of the drawing board.

According to my invention l attach to any drawing board a guide-plate ofmetal adapted to guide and check the movement of a slotted back-square,the latter forming the head of the T-square and being provided with ahand-operated clamping device by means of which the back-square may bemoved and fixed in any position within the said guide-plate.

For a clear understanding of the inven- Serial No. 627,747.

tion I refer to the accompanying drawings, in which l,

Fig. 1 shows a side elevation of the T- square-guide as attached to adrawing board, the latter only partly being illustrated;

Fig. 2 shows a section, partly in elevation, of the aforesaidbach-square with the clamping device;

Fig. 3 shows a perspective view of part of a drawing board with theguide-plate secured thereto;

Fig. a shows an elevation, partly in section, of the hand-operatedclamping device; Fig. 5 is a lateral section through parts of the deviceillustrated in Fig. 2l;

Fig. 6 represents a plan view'of the clamping device;

Fig. 7 is a perspective view of the back- 70 square and certain otherparts;

F ig. 8 is a sectional view of details, and

Fig. 9 shows a plan view of the backsquare and the guide-plate mountedon a drawing board.

Referring to these drawings, 1 designates a drawing board of anysuitable size, to the underside of one edge of which and exactlyparallel thereto an angle-shaped guideplate 2 is secured by means ofscrews 3 en and washers 4. Each end of the guideplate is formed with aninternally screwthreaded nave, as at 28, to receive a pin 24 the pointedend of which, when the pin is screwed into the nave, is made topenetrate into the drawing board thus assisting in steadying the plate 2and preventing any accidental displacement thereof. The guideplateserves for the reception of a backs uare 6 made, for instance, of woodor a0 celluloid and provided with metal strips 7 at its base to makecontact with and ensure smooth sliding along the edge of the drawingboard l. The central portion of the back-square 6 has recesses 8 formedtherein e5 of the shape most clearly shown in Figs. 2 and 7. Mountedwithin these recesses is a clamping device adapted to secure theback-square in the guide-plate or release it when it is desired to movethe back-square along the said guide-plate. A member 9 of wood or othersuitable maf/@rial attached to the top of the back-square and coveringthe recesses 8 forms With the said backsquare the T-square proper.

The aforementioned clamping device coinprises an arm 10, an integralsleeve 11 at one end thereof, and a clamping member 18 at the other endto tightly abut against or clamp the vertical portion of the guideplate,the arm 10 being pivoted to a bridgepiece 12 fitted Within the recesses8. Also located in these recesses and secured to the back-square 6 is aspring guide 2O carrying a pin 19, this pin receiving one end of a coilspring 17 of which the other end tends to press against the head 16 ofthe sleeve 11. The screw-threaded head of the sleeve is fitted With acap 18, the latter and the sleeve thus forming a handle -for operatingthe clamping device.

By applying pressure upon the cap 18, the arm 10 is made to swing aboutits pivot at 12 and the clamping member 13 caused to be disengaged fromthe guideplate 2, so that the back-square 6 and the member 9, that is,the T-square may be freely moved along the guide-plate. As soon as thepressure on the cap 18 is released, the clamping member 13 is once moremade to press against the guide-plate and thereby secures the T-squarein position. A slot 21 longitudinally arranged in the bottom portion ofthe back-square and receiving the vertical part of the guide-plate 2ensures a true parallel movement of the back-square.

Having now fully described my said invention What I claim and desire tosecure by Letters Patent is :M

ln a lu-square-guide for drawing boards, the combination, With anangle-shaped guide-plate attached to the underside of the drawing boardand parallel to one Working edge thereof, and a longitudinally slottedand centrally recessed back-square Which forms part of the lsquare andis slidably mounted in the guide-plate, of a clamping device forsecuring the back-square in any position Within the guideplate, the saidclamping device comprising an arm pivotally mounted in the recessed partof the backsquare, a handle formed at one end of the arm, a clampingmember fashioned at the other end of the arm and abutting against theinner Vside of the vertical member of the guide-plate, and a spring alsomounted Within the aforesaid recessed part and tending to press againstthe handle end of the arm and causing the clamping member to tightlyengage the said vertical member of the guide-plate, all as and for thepurpose set forth. n

FRANZ KUTTEL. In the presence of- JAMES J. MURPHY, Jr., Een. COLEREWAons.

